Lactate-induced autophagy activation: unraveling the therapeutic impact of high-intensity interval training on insulin resistance in type 2 diabetic rats.

Impaired autophagy is a hallmark of diabetes. The current study proposed to investigate if high intensity interval training (HIIT) induced lactate accumulation could stimulate autophagy in type 2 diabetic male rats. 28 male Wistar rats were randomly assigned into four groups: Healthy Control (CO), Diabetes Control (T2D), Exercise (EX), and Diabetes + Exercise (T2D + EX). Diabetes was induced by feeding high-fat diet and administrating single dose of streptozotocin (35 mg/kg). After becoming diabetic, the animals in the exercise groups (EX and T2D + EX) performed an eight-week HIIT (4-10 interval, 80-100% Vmax, 5 days per week). Serum levels of lactate, glucose and insulin as well as the levels of lactate, pyruvate, lactate transporter monocarboxylate transporter 1 (MCT1), phosphorylated mitogen-activated protein kinases (p-MAP 1 and 2), phosphorylated extracellular signal-regulated protein kinases 1 and 2 (p-ERK 1 and 2), mammalian target of rapamycin (p-mTOR), ribosomal protein S6 kinase beta-1 (p-70S6k), p90 ribosomal S6 kinases (p-90RSK), autophagy related 7 (ATG7), Beclin-1, microtubule-associated protein 1A/1B, and 2A/2B -light chain 3 levels (LC3-I), (LC3- II), (LC3I/LC3II) in soleus muscle were measured. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and serum glucose was lower in T2D + EX compared to T2D group (P < 0.0001). While serum and soleus muscle levels of lactate was not different between T2D and T2D + Ex, the levels of Pyruvate (P < 0.01), MCT1, p-ERK1/2, p-mTOR, p70S6k, P-90RSK, ATG7, LC3-II, and LC3-II/LC3I ratios were higher in T2D + EX compared to T2D group (P < 0.0001). We concluded that eight weeks of high-intensity interval training could activated ERK/P90SRK while inhibiting mTOR/P70S6K signaling pathway in lactate dependent manner. It means increased autophagy which resulted in improve insulin resistance (IR) and reduce blood glucose.

Quercetin as a therapeutic agent activate the Nrf2/Keap1 pathway to alleviate lung ischemia-reperfusion injury.

Lung ischemia-reperfusion injury (LIRI) causes oxidative stress, inflammation, and immune system activation. The Nrf2/Keap1/HO-1 pathway is important in cellular defense against these effects. Quercetin, a flavonoid with antioxidant, anti-inflammatory, and anti-cancer properties, has been investigated. Our aim in this study was to investigate the effect of quercetin on preventing lung ischemia-reperfusion injury and the role of the Nrf2/Keap1/HO-1 pathway. Sixty-four male Wistar rats were divided into four distinct groups(n = 16). Sham, lung ischemia-reperfusion (LIR), Saline + LIR, Quercetin + LIR (30 mg/kg i.p for a week before LIR). LIR groups were subjected to 60 min of ischemia (left pulmonary artery, vein, and bronchus) and 120 min of reperfusion. Our assessment encompassed a comprehensive analysis of various factors, including the evaluation of expression Nrf2, Keap1, and Heme Oxygenase-1 (HO-1) levels and NF-κB protein. Furthermore, we examined markers related to inflammation (interleukin-1ß and tumor necrosis factor alpha), oxidative stress (malondialdehyde, total oxidant status, superoxide dismutase, glutathione peroxidase, total antioxidant capacity), lung edema (Wet/dry lung weight ratio and total protein concentration), apoptosis (Bax and Bcl2 protein), and histopathological alterations (intra-alveolar edema, alveolar hemorrhage, and neutrophil infiltration). Our results show that ischemia-reperfusion results in heightened inflammation, oxidative stress, apoptosis, lung edema, and histopathological damage. Quercetin showed preventive effects by reducing these markers, acting through modulation of the Nrf2/Keap1 pathway and inhibiting the NF-κB pathway. This anti-inflammatory effect, complementary to the antioxidant effects of quercetin, provides a multifaceted approach to cell protection that is important for developing therapeutic strategies against ischemia-reperfusion injury and could be helpful in preventive strategies against ischemia-reperfusion.